1. Field of the Invention
The present invention relates to a device for mounting an electronic part with a lead wire to a printed wiring board, and particularly relates to an electronic parts insertion head for automatically inserting the electronic part into an attaching hole of the printed wiring board.
2. Related Background Art
An insertion guide mechanism of electronic parts is proposed in Japanese Utility Model Registration No. 3-33114, etc. In this insertion guide mechanism, a lead wire of an electronic part is inserted into an attaching hole of a printed wiring board by pushing down a top portion of the electronic part by a pushing rod from above while the lead wire of the electronic part is nipped and guided by an insertion guide.
In such an electronic parts insertion mechanism, the above insertion guide guides the lead wire of the electronic parts in a guide position near the attaching hole of the printed wiring board. When the insertion of one electronic part is completed, the insertion guide is raised to a receiving position higher than the guide position so as to receive the next electronic part. An electronic parts insertion head adopted in the conventional electronic parts insertion mechanism is constructed such that a lower end of the insertion guide is returned to the raised position drawing a constant locus in a returning operation to the raised position of the insertion guide after each electronic part is inserted into the printed wiring board. Therefore, in an insertion guide suitable for the insertion of relatively thin electronic parts such as a ceramic capacitor, when electronic parts of a large diameter such as an electrolytic capacitor are inserted, the electronic parts of a large diameter become a hindrance in the returning operation of the insertion guide after the insertion. Therefore, the insertion guide and the electronic parts interfere with each other so that returning operation cannot be performed. On the other hand, when relatively thin electronic parts such as a ceramic capacitor are inserted by the insertion guide suitable for the insertion of large electronic parts such as an electrolytic capacitor, a runout in the returning operation of the insertion guide after the insertion is unnecessarily large. Therefore, mounting density in attachment of the electronic parts to the printed wiring board cannot be increased.
An electronic parts insertion head as a measure for solving such a problem is proposed in Japanese Patent Publication No. 7-58839. In this electronic parts insertion head, a locus of the rising insertion guide can be changed by changing a position of the fulcrum shaft of a link for supporting the insertion guide. In an example of this construction, the fulcrum shaft of the link is moved by using a piston driven by the air so that the position of the link fulcrum shaft with respect to a supporting block is changed. The position of the fulcrum shaft is moved between predetermined first and second positions and two loci of the rising insertion guide can be switched in accordance with these positions.
In the electronic parts insertion head as disclosed in the above Japanese Patent Publication No. 7-58839, the loci for the rising insertion guide, in which the insertion guide runs away from the electronic parts inserted into the attaching hole of the printed wiring board, are switched by changing the position of the fulcrum shaft of the link for supporting the insertion guide with respect to the supporting block from the first position to the second position. In the example of Japanese Patent Publication No. 7-58839, the fulcrum shaft is moved by the piston driven by the air in the switching of the above rising loci. When the insertion head is in the lowered position, it is necessary to locate the insertion guide at a predetermined position so as to insert the lead wire of the electronic part into the attaching hole of the printed wiring board. On the other hand, when the insertion head is in the raised position, it is also necessary to locate the insertion guide in a predetermined position so as to receive the lead wire of the electronic part supplied from a parts supplying system. Accordingly, when the predetermined position of the insertion guide in the reception of the electronic parts corresponds to, for example, the first position of the above fulcrum shaft of the link and the locus corresponding to the second position of the fulcrum shaft is selected, the position of the fulcrum shaft must be changed to the first position by supplying the air every time the insertion head is raised. Namely, a switching operation of the locus is required every time the insertion head is raised and lowered.
An object of the present invention is to increase stability, efficiency and speed of the operation of an electronic parts insertion head such that no switching operation is performed when the same state of a rising locus is continued. The other objects will be described in the explanation of embodiments.
To solve the above problems, an electronic parts insertion head in the present invention comprises:
a supporting block;
an insertion guide movable between first and second positions with respect to the supporting block and guiding a lead wire of an electronic part to an attaching hole of a printed wiring board in the first position;
an insertion guide moving mechanism for moving the insertion guide between the first and second positions;
a cam capable of changing its position with respect to the supporting block; and
a cam follower arranged on the insertion guide and moved along a cam face of the cam while being in contact with the cam face during the movement of the insertion guide between the first and second positions; and
a cam position changing mechanism for changing the position of the cam, in which
a locus of the movement of the insertion guide can be changed by changing the position of the cam by the cam position changing mechanism.
In the normal construction of the device, the printed wiring board is arranged below the electronic parts insertion head. Accordingly, the above first position becomes a lowered position lower than the above second position and the second position becomes a raised position.
In one constructional example of the above electronic parts insertion head, the insertion guide further has a biasing means connected to the supporting block by an arm having one end pivotally supported by the supporting block and the other end pivotally supported by the insertion guide, the biasing means constantly biasing the insertion guide to make the cam follower of the insertion guide come in contact with the cam face so that the moving locus of the insertion guide is determined by constraint due to the arm and the contact of the following portion and the cam face.
In the above electronic parts insertion head, the cam position is preferably changed by the cam position changing means with pneumatic pressure as a driving source.
When this electronic parts insertion head is embodied, it is preferable to arrange an electric parts pressing mechanism for pressing the electronic part to insert the lead wire thereof into the attaching hole of the printed wiring board to a desired depth by applying force to the electronic parts.
An important feature the above electronic parts insertion head of the present invention is that the cam face (or a shape of the cam face) coming in contact with the cam following portion during the movement of the insertion guide can be changed so that the locus of the movement of the insertion guide can be changed. It should be understood that the cam face coming in contact with the cam follower during the movement of the insertion guide can be changed by other ways that are different from changing the position of the single cam. Namely, the cam face coming in contact with the cam follower during the movement of the insertion guide may also be changed by, for example, arranging plural cams and switching these cams. In this case, the electronic parts insertion head is defined as follows.
The electronic parts insertion head comprises:
a supporting block;
an insertion guide movable between first and second positions with respect to the supporting block and guiding a lead wire of an electronic part to an attaching hole of a printed wiring board in the first position;
insertion guide moving means for moving the insertion guide between the first and second positions; and
a cam mechanism including cam means and a cam follower that is arranged on the insertion guide and adapted to move along a cam face of the cam means while being in contact with the cam face when the insertion guide is moving between the first and second positions, in which
the cam face coming in contact with the cam follower at a moving time of the insertion guide can be changed in the cam mechanism so that a locus of the movement of the insertion guide can be changed.
However, it is preferable to use the above construction in which the cam means of the cam mechanism is constructed by a single cam, and the cam position changing mechanism for changing the position of the cam with respect to the above supporting block is arranged, and the cam face coming in contact with the cam following portion at the moving time of the insertion guide is changed by changing the position of the cam. This is because the number of cams is one, and the shape of the cam face coming in contact with the cam following portion can be simply changed by switching the position of the cam. Accordingly, this construction is simple and preferable in comparison with a construction for switching plural cams.
The present invention also provides an electronic parts insertion device comprising: a parts supplying mechanism for supplying an electronic part having a lead wire; an electronic parts insertion head for receiving the electronic part from the parts supplying mechanism and inserting the lead wire of the electronic part into an attaching hole of a printed wiring board; and a clinch mechanism for cutting, bending and fixing the lead wire of the electronic part inserted into the printed wiring board, in which
the electronic parts insertion head comprises:
a base;
an insertion guide movable between first and second positions with respect to the base and guiding the lead wire of the electronic part to a position of the attaching hole of the printed wiring board in the first position;
insertion guide moving means for moving the insertion guide between the first and second positions;
a cam capable of changing its position with respect to a body of the electronic parts insertion head;
a cam follower arranged on the insertion guide and moved along a cam face of the cam while being in contact with the cam face during the movement of the insertion guide between the first and second positions; and
a cam position changing mechanism for changing the position of the cam, and is characterized in that
a locus of the movement the insertion guide can be changed by changing the position of the cam by the cam position changing mechanism.
In one constructional example of the above electronic parts insertion device, the insertion guide further has biasing means connected to the base by an arm having one end pivotally supported by the base and the other end pivotally supported by the insertion guide, the biasing means constantly biasing the insertion guide such that the cam follower of the insertion guide comes in contact with the cam face, and the locus of the movement of the insertion guide is determined by constraint due to the arm and by the contact between the following portion and the cam face.
In the above electronic parts insertion device, the cam position is preferably changed by the cam position changing mechanism with pneumatic pressure as a driving source.
When this electronic parts insertion device is embodied, an electric parts pressing means for pressing the electronic part to insert the lead wire thereof into the attaching hole of the printed wiring board to a desired depth by applying force to the electronic part is normally preferably arranged in the electronic parts insertion head.
In the electronic parts insertion head or the electronic parts insertion device of the present invention explained above, the movement locus of the insertion guide in the movement from the first position to the second position (namely, at a rising time of the insertion guide) can be changed by merely changing the position of the cam. Namely, a rising and retreating locus of the insertion guide can be changed in accordance with thicknesses and diameters of the electronic parts. Then, various loci can be formed by merely changing the cam face of the above cam and a cam curved surface. Accordingly, a very flexible construction, i.e., a construction having a high degree of freedom in setting of the locus is obtained in comparison with a case in which the locus is determined by design of the insertion head.
Further, it is not necessary to return the insertion guide in a position in which the insertion guide receives the electronic part from a delivery chuck. When electronic part of the same kind in thickness and diameter continue, operation for changing the locus of the insertion head need not be performed every time so that the more stable operation is performed at a high speed. Further, an operating time for changing the locus is sufficiently allocated in comparison with a conventional case. Further, the electronic parts of from a small diameter to a large diameter can be automatically inserted by a selection using a program set in advance without exchanging the insertion guide, etc.